Cellulose production by Acetobacter acetigenum in defined medium

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Abstract
Growth and cellulose production by Acetobacter acetigenum strain EA-I was limited by nitrogen concentrations below 0.01% (w/v) in glucose defined medium. Ammonium sulphate and asparagine + glutamic acid (50% of each) were equivalent as nitrogen sources when compared on a nitrogen weight basis over the range 0.001-0.1%-N; at higher concentrations ammonium sulphate decreased growth and cellulose synthesis, while asparagine + glutamic acid became stimulatory. When used as adjuncts in glucose defined medium, acetate, citrate and succinate at suitable concentrations increased growth and cellulose synthesis, by as much as 20-30-fold under the most favourable conditions. Ethanol stimulated growth but did not increase cellulose synthesis. The addition of calcium or magnesium carbonate to defined medium inhibited growth. The influence of glucose concentration in defined medium on growth and cellulose synthesis was relatively slight in the absence of succinate; in the presence of 0.084[image]-succinate the cultures showed a much greater response to glucose concentration, with a maximum cellulose yield that was 7.6 times greater than the maximum in the absence of succinate, and was associated with a 1.9-fold increase in growth. In hydrolysed molasses medium the addition of succinate decreased growth and cellulose synthesis; slightly increased cellulose yields were obtained when ethanol and calcium carbonate were added.